Production of thymol



Patented July 5, 1932 l i UNITED STATES WALTER SCHOELLER, or BERLIN-cHARLoTTEunURG, HANS JORDAN, or BERLIN-STEG- LI'rz, AND REINHARD CLERC, or BERLIN, GERMANY, essrouons 'ro SGHERING- KAHLBAUM .A.-G., or BERLIN, GERMANY raonucrrou on'rnmot p No Drawing. Application filed .Tune' 29, 1928, Serial Noh28 932 4, and-in Germany'J'my 15, 19 27. L

Our invention refers to the production of thymol. As it is shown in the applications for patent of the United States, Serial No. 200,289, filed by Hans Jordan June 20, 1927 and Ser. No. 287,639, filed by Walter Schoeller, Hans Jordan and Reinhard Clerc June 22, 1928, various condensation products are obtained by Condensation of meta-cresol and acetone, according to the conditions selected.

At a temperature somewhat above room temperature but below 100 C. a polymerization product of the formula (3 11 0 which contains but one hydroxyl group capable of acetylation is obtained upon condensation of 15 meta-cresol and acetone in the presence of an acidic condensation medium. This product probably has the following formula:

I At a lower temperature of approximately from 0 C. to 10 0., a condensation product.

of the formula C H O is produced containing in the molecule two hydroxyl groups capable of acetylation, and which probably has the following formula:

(lJHa fabi'litated if the condensation products'of 'met'a-cresol and'ace'tone described above are first acyl ated and then subjected to tlie thernial decomposition, The acyl compounds of '3-me thyl-6-isopropylene thus obtained, show no tendency to polymerization, they can be transformed by treating with hydrogen in the presence of a hydrogenation catalyst into 'fying into thymol. V a p Theacylating of the condensation-product from in'e'ta-cresol and acetone is effected in the usualmanner for example by boiling with acetic anhydride in the presence of sodium acetate or sulphuric acid. i

' The following examples illustrate the i nvention I V V Emample l I V The monoacetylcompound of the formula i Us: 3H: i

7 H20, CH: 7 I 1 of thecondensation product from meta-cres01 and acetoneimelting at 122 -123 (3;, which can -be obtained by condensing meta-cresol andacetone by means of an acidiccondens+ ing agent atatemperature of 3040 C. and then'acetylating, is heated in a distillation vessel toabout 300-320 C. this condensation product having'the following formula A mixture-bf methyl isopropylene-phenolacetate and methyl-i'sopropylene-phenol distills over. This mixture in the presence of a nickel catalyst is then hydrogenated to thy- IPAIENTOFFICB thymol-acylate and subsequently by saponimol and thymol acetate by treating with hydrogen in the presence of a hydrogenation catalyst. By saponification of the mixture, the acetate is converted into thymol.

, Emample 2 The diacetyl'compound of 4:,4'-dimethyl-2, 2-dihydroxydiphenyldimethylmethane melting at S L- C. which can be obtained-according to Example 1 of the application for patent of the U. S. Ser. No. 287,639 filed J une,

22, 1928, is heated in a distillation Vessel to about 310-330 C. It decomposes into cresol acetate and methyl isopropylene phenol acetate-which in the presence of a nickel catalyst is then hydrogenated with the addition of 2 atoms of hydrogen and saponified to thymol.

Various changes may be made in the details disclosed in the foregoing specification without departing from the invention or sacrificing the advantages thereof.

We claim:

1. The process of producing thymol comprising heating an acylcompound of acoudensation product obtained from meta-cresol and acetone at temperatures below C. in the presence of an acidic condensing agent, belongingto' the group consisting of hydrochloric acid, phosphorus oxychloride and anhydrous metallic chlorides and treating the acylcompound of 8-methyl-6-isopropylone-phenol thus obtained. with hydrogen in the presence of a hydrogenation catalyst until two atoms of hydrogen have been taken up and subsequently saponifying the product.

2. The process of producing thymol comprising heating an acetylcompound of a con densation product obtained from meta-cresol and acetone at temperatures below 100 C. in the presence of an acidic condensing agent, belonging to the group consisting of hydrochloric acid, phosphorus oxychloride and anhydrous metallic chlorides andtreating the acetylcompound of 3-methyl-6-isopropylene phenol thus obtained with hydrogen inthe presence of a hydrogenation catalyst until two atoms of hydrogen have'been taken up and subsequently'saponifying the product. i

3. The process of producing thymol comprising heating the diacetylcompound of 4,4 dimethyl -2,2-dihydroxydiphenyldimethylmethane and treating the methylisopropylenephenylacetate thus obtained with hydrogen in the presence of a hydrogenationcatalyst until two atoms of hydrogen have been taken up and subsequently saponifying the product.

. WALTER SCHOELLER.

- ,HANS JORDAN. REINHARD' CLERO. 

